title: Treatment times of Class II malocclusion: four premolar and non-extraction protocols.
abstract: The purpose of this study was to retrospectively compare the treatment times of Class II division 1 malocclusion subjects treated with four first premolar extractions or a non-extraction protocol and fixed edgewise appliances. Eighty-four patients were selected and divided into two groups. Group 1, treated with four first premolar extractions, consisted of 48 patients (27 males and 21 females) with a mean age of 13.03 years and group 2, treated without extractions, consisted of 36 patients (18 males and 18 females) with a mean age of 13.13 years. Group 2 was subdivided into two subgroups, 2A consisting of 16 patients treated in one phase and 2B consisting of 20 patients treated in two phases. The initial and final Treatment Priority Index (TPI), initial ages, initial mandibular crowding, and treatment times of groups 1 and 2 were compared with t-tests. These variables were also compared between group 1 and the subgroups with analysis of variance followed by Tukey's tests. The treatment times for groups 1 and 2 and subgroups 2A and 2B were 2.36, 2.47, 2.25, and 2.64 years, respectively, which were not significantly different. Treatment times with non-extraction and four premolar extraction protocols are similar.
authors.affiliation: Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil. jansong@travelnet.com.br
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
authors.forename: Danilo Pinelli
authors.initials: DP
authors.lastname: Valarelli
authors.forename: Fabrício Pinelli
authors.initials: FP
authors.lastname: Valarelli
authors.forename: Marcos Roberto
authors.initials: MR
authors.lastname: de Freitas
mesh_terms: D000202:Activator Appliances; D000293:Adolescent; D001641:Bicuspid / Q000601:surgery*; D016022:Case-Control Studies; D002648:Child; D003724:Dental Arch / Q000473:pathology; D005115:Extraoral Traction Appliances; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008963:Molar / Q000473:pathology; D024343:Open Bite / Q000628:therapy; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation; D016910:Orthodontic Brackets; D057887:Overbite / Q000628:therapy; D012189:Retrospective Studies; D013997:Time Factors; D019228:Tooth Crown / Q000473:pathology; D014081:Tooth Extraction / Q000379:methods*; D014087:Tooth Movement Techniques / Q000295:instrumentation; D016896:Treatment Outcome